Arylsulfatases A and B have been shown to have elevated levels in osteoarthritic articular cartilage. In order to determine factors which influence the de novo synthesis and regulation of their activities, these enzymes will be isolated and purified from chondrocytes grown in culture. Chondrocyte culture systems from normal and osteoarthritic human articular cartilage will be employed to examine and compare the effects of hyaluronic acid, insulin, somatomedin, factors isolated from normal and osteoarthritic human sera, and synovial fluid on sulfated proteoglycan metabolism. We propose to identify, isolate, and purify the enzymes responsible for the desulfation of chondroitin sulfate, the principal glycosaminoglycan component in adult human articular cartilage. A possible relationship of these enzymes to the purified arylsulfatases will be investigated. The physiological substrates in cartilage for the arylsulfatases will be characterized and compared with those described for other tissues. If, as has been shown for the latter, the substrates are also oligosaccharide sulfates, the presence of a "chondroitinase" type of enzyme, reported to be present in epiphyseal cartilage, will be sought in human articular cartilage. Proteoglycans will be isolated from normal and osteoarthritic human articular cartilage. The physical-parameters of these molecules will be compared in terms of size and aggregating ability. In the broadest sense, this research is directed toward a better understanding of the regulation of proteoglycan metabolism under different physiological conditions with a view to facilitating early diagnosis and providing a rationale for non-surgical therapy in osteoarthritis.